Xanthophylls are yellow pigments that form one of two major divisions of the carotenoid group. Their molecular structure is similar to carotenes, which form the other major carotenoid group division, but xanthophylls contain oxygen atoms, while carotenes are purely hydrocarbons with no oxygen. Xanthophylls contain their oxygen either as hydroxyl groups and/or as pairs of hydrogen atoms that are substituted by oxygen atoms acting as a bridge (epoxide).
Like other carotenoids, xanthophylls are found in highest quantity in the leaves and/or flowers of most green plants, where they act to modulate light energy. The xanthophylls found in the bodies of animals, and in dietary animal products, are ultimately derived from plant sources in the diet. For example, the yellow color of chicken egg yolks, fat, and skin comes from ingested xanthophylls (primarily lutein, which is often added to chicken feed for this purpose).
The yellow color of the human macula lutea in the retina of the eye comes from the lutein and zeaxanthin it contains, both xanthophylls again requiring a source in the human diet to be present in the eye. These function in eye protection from ionizing blue light, which they absorb.
The group of xanthophylls includes (among many other compounds) lutein, zeaxanthin, neoxanthin, violaxanthin, and α- and β-cryptoxanthin.
There is an interest in developing products that have high levels of xanthophylls. For example, xanthophylls are known to have antioxidant properties and have been shown to prevent age-related macular degeneration (AMD).
Marigold flowers are the most commercially significant source of xanthophylls. Most marigold plants used for the production of xanthopylls are grown from hybrid seed produced by the crossing of a male line and a female line. Accordingly, male and/or female lines of marigold having high levels of xanthophylls can be used to create hybrid seed that can be used to grow hybrid marigold plants with elevated levels of xanthophylls, and thereby improve the economy of producing xanthopylls for the commercial marketplace, particularly if the hybrid plants have a large biomass of flowers that can be reliably harvested.